<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
</head>

<body>
    <div id="app">asdfasdf</div>

    <script>
        // 创建jQuery对象
        // 方法1 $(选择器)
        // var obj = {};
        // var date = new Date();

        var $app = $('#app');
        console.log('$app', $app);


        // 方式2 $(原生dom节点)
        var app = document.querySelector('#app');
        console.log('app', app);
        var $app = $(app);
    </script>
</body>

</html>